Electric therapy systems including therapy devices and external devices are known in the art. The therapy device of such a system may be an implant, for example, such as an implantable heart pacemaker, cardioverter/defibrillator or the like. The external device may be a programming device for such a therapy device, or a so-called patient device that serves as a relay station between the implant and a central service center.
The data communication interface of the therapy device (the therapy device data communication interface) and the data communication interface of the external device (the external device data communication interface) each have a transmitter and a receiver (together also known as a transceiver) to allow bidirectional data communication.
In the case of implantable heart pacemakers or cardioverters/defibrillators, the therapy device, e.g., the implant, often has two data communication interfaces. One of these therapy device data communication interfaces will often use an alternating magnetic field for wireless data communication. This data communication is usually used between a programming device and the implant and has only a very short range. This data communication is used, for example, when a patient who has a heart pacemaker is visiting his treating physician. The physician may then place a corresponding programming head of the programming device against the patient's body, thereby enabling short-range data communication between the implant and the programming head via an alternating magnetic field.
A second therapy device data communication interface is often provided for a somewhat longer-range data communication with an external device. This external device may be either a programming device or a patient device, which often serves as a relay station for data communication between an implant and a remote service center. Data communication may take place here via an alternating electric field in the so-called MICS band. The MICS band is a special frequency band for data communication between implants and external devices.
In any case, the at least one therapy device data communication interface of the implant must be supplied with power by a power source provided internally within the implant, which is typically a battery that inherently has only a limited capacity. If the battery of an implant, e.g., an implantable heart pacemaker, is depleted, the heart pacemaker must be explanted in a surgical procedure and replaced by a new one. There is therefore a need to minimize the power consumption by the therapy device. This requirement also applies to the power consumption for the bidirectional data link.